Field of the Invention
The present invention relates to an image forming apparatus, such as a copier, a printer, a facsimile, or a multifunction machine, configured to form an image on a sheet.
Description of the Related Art
Some related-art electrophotographic image forming apparatuses, such as a copier or a printer, employ intermediate transfer belts as transfer belts. In such an image forming apparatus employing an intermediate transfer belt, a full-color image is formed through a primary-transfer step and a secondary-transfer step.
In the primary-transfer step, a toner image formed on a surface of an electrophotographic photoconductive member is primarily transferred to the intermediate transfer belt. The primary-transfer step is performed for forming each of a plurality of toner images in different colors, whereby a combination of toner images in different colors is formed on the intermediate transfer belt. In the secondary-transfer step, the combination of toner images in different colors is transferred to a surface of a transfer material such as a piece of paper. The combination of toner images thus transferred to the transfer material is then fixed by a fixing device. Thus, a full-color image is obtained.
A transfer device included in such an image forming apparatus includes a transfer member in the form of a roller, a blade, a brush, or the like. The transfer member is a contact member that is provided in contact with the inner peripheral surface of the intermediate transfer belt at a position across from the photoconductive member.
In Japanese Patent Laid-Open No. 2011-248385, an image forming apparatus including a brush-type transfer member as a transfer device is disclosed. The brush-type transfer member according to Japanese Patent Laid-Open No. 2011-248385 includes a stainless-steel metal holder (a supporting member) that supports a brush thereon with the aid of two-sided adhesive tape. The brush include a plurality of conductive fibers. That is, the transfer member according to Japanese Patent Laid-Open No. 2011-248385 is disclosed as a brush-type rubbing member that is unrotatably in contact with the intermediate transfer belt and thus rubs the intermediate transfer belt.
Employing such a rubbing member as in Japanese Patent Laid-Open No. 2011-248385 generates a large frictional force between the rubbing member and the intermediate transfer belt and may lead to, for example, bending of the rubbing member or the supporting member or generation of noise due to vibration of the rubbing member or the supporting member caused by a stick-slip phenomenon or the like. Such a condition occurs not only in the case of the intermediate transfer belt but also in a case of a conveying belt that bears and conveys the transfer material and in a case of any other rubbing member that may vibrate by rubbing a moving object provided in the image forming apparatus.